lately ive been thinking of increasing initial acceleration in the kizashi, especially after the post that recommended the "pedalbox" throttle. Is this a trustworty modification that works? are there any other alternative modifications/driving techniques that can improve initial acceleration? can the cvt tran handle a higher acceleration?

Initial standing-start acceleration is limited, by design, electronically due the fact that the JF011E is a boarder line adequate size unit to propel the Kizashi. If not limited by the controls, it would likely grenade prematurely. Sorry, no hole-shots in a CVT vehicle of any kind to my knowledge.

I can tell you with certainty what has dramatically increased my 82,000 mile car's throttle response, acceleration, and fuel economy was its very first CVT fluid and filters changes recently completed on the CVT.